<!-- Creator : groff version 1.19.2 -->
<!-- CreationDate: Wed Jan 2 08:39:52 2013 -->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta name="generator" content="groff -Thtml, see www.gnu.org">
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<meta name="Content-Style" content="text/css">
<style type="text/css">
p { margin-top: 0; margin-bottom: 0; }
pre { margin-top: 0; margin-bottom: 0; }
table { margin-top: 0; margin-bottom: 0; }
</style>
<title>GRDPROJECT</title>
</head>
<body bgcolor="#ffffff">
<h1 align=center>GRDPROJECT</h1>
<a href="#NAME">NAME</a><br>
<a href="#SYNOPSIS">SYNOPSIS</a><br>
<a href="#DESCRIPTION">DESCRIPTION</a><br>
<a href="#OPTIONS">OPTIONS</a><br>
<a href="#GRID FILE FORMATS">GRID FILE FORMATS</a><br>
<a href="#EXAMPLES">EXAMPLES</a><br>
<a href="#RESTRICTIONS">RESTRICTIONS</a><br>
<a href="#SEE ALSO">SEE ALSO</a><br>
<hr>
<a name="NAME"></a>
<h2>NAME</h2>
<p style="margin-left:11%; margin-top: 1em">grdproject
− Forward and Inverse map transformation of 2-D grid
files</p>
<a name="SYNOPSIS"></a>
<h2>SYNOPSIS</h2>
<p style="margin-left:11%; margin-top: 1em"><b>grdproject</b>
<i>in_grdfile</i> <b>−G</b><i>out_grdfile</i>
<b>−J</b><i>parameters</i> [
<b>−A</b>[<b>k|m|n|i|c|p</b>] ] [
<b>−C</b>[<i>dx/dy</i>] ] [
<b>−D</b><i>xinc</i>[<i>unit</i>][<b>=</b>|<b>+</b>][/<i>yinc</i>[<i>unit</i>][<b>=</b>|<b>+</b>]]
] [ <b>−E</b><i>dpi</i> ] [ <b>−F</b> ] [
<b>−I</b> ] [
<b>−Mc</b>|<b>i</b>|<b>m</b>|<b>p</b> ] [
<b>−N</b><i>nx/ny</i> ] [
<b>−R</b><i>west</i>/<i>east</i>/<i>south</i>/<i>north</i>[<b>r</b>]
] [
<b>−S</b>[<b>-</b>]<b>b</b>|<b>c</b>|<b>l</b>|<b>n</b>[<b>/</b><i>threshold</i>]
] [ <b>−V</b> ]</p>
<a name="DESCRIPTION"></a>
<h2>DESCRIPTION</h2>
<p style="margin-left:11%; margin-top: 1em"><b>grdproject</b>
will do one of two things depending whether <b>−I</b>
has been set. If set, it will transform a gridded data set
from a rectangular coordinate system onto a geographical
system by resampling the surface at the new nodes. If not
set, it will project a geographical gridded data set onto a
rectangular grid. To obtain the value at each new node, its
location is inversely projected back onto the input grid
after which a value is interpolated between the surrounding
input grid values. By default bi-cubic interpolation is
used. Aliasing is avoided by also forward projecting the
input grid nodes. If two or more nodes are projected onto
the same new node, their average will dominate in the
calculation of the new node value. Interpolation and
aliasing is controlled with the <b>−S</b> option. The
new node spacing may be determined in one of several ways by
specifying the grid spacing, number of nodes, or resolution.
Nodes not constrained by input data are set to NaN. <br>
The <b>−R</b> option can be used to select a map
region larger or smaller than that implied by the extent of
the grid file. <i><br>
in_grdfile</i></p>
<p style="margin-left:22%;">2-D binary grid file to be
transformed. (See GRID FILE FORMATS below.)</p>
<table width="100%" border=0 rules="none" frame="void"
cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−G</b></p> </td>
<td width="8%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Specify the name of
the output grid file. (See GRID FILE FORMATS below.)</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−J</b></p> </td>
<td width="8%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Selects the map
projection. Scale is UNIT/degree, 1:xxxxx, or width in UNIT
(upper case modifier). UNIT is cm, inch, or m, depending on
the <b><A HREF="gmtdefaults.html#MEASURE_UNIT">MEASURE_UNIT</A></b> setting in .gmtdefaults4, but this
can be overridden on the command line by appending <b>c</b>,
<b>i</b>, or <b>m</b> to the scale/width value. When central
meridian is optional, default is center of longitude range
on <b>−R</b> option. Default standard parallel is the
equator. For map height, max dimension, or min dimension,
append <b>h</b>, <b>+</b>, or <b>-</b> to the width,
respectively.</p> </td>
</table>
<p style="margin-left:22%;">More details can be found in
the <b><A HREF="psbasemap.html">psbasemap</A></b> man pages.</p>
<p style="margin-left:22%; margin-top: 1em"><b>CYLINDRICAL
PROJECTIONS:</b></p>
<p style="margin-left:22%; margin-top: 1em"><b>−Jc</b><i>lon0/lat0/scale</i>
(Cassini) <b><br>
−Jcyl_stere</b>/[<i>lon0/</i>[<i>lat0/</i>]]<i>scale</i>
(Cylindrical Stereographic) <b><br>
−Jj</b>[<i>lon0/</i>]<i>scale</i> (Miller) <b><br>
−Jm</b>[<i>lon0</i>/[<i>lat0/</i>]]<i>scale</i>
(Mercator) <b><br>
−Jm</b><i>lon0/lat0/scale</i> (Mercator - Give
meridian and standard parallel) <b><br>
−Jo</b>[<b>a</b>]<i>lon0/lat0/azimuth/scale</i>
(Oblique Mercator - point and azimuth) <b><br>
−Jo</b>[<b>b</b>]<i>lon0/lat0/lon1/lat1/scale</i>
(Oblique Mercator - two points) <b><br>
−Joc</b><i>lon0/lat0/lonp/latp/scale</i> (Oblique
Mercator - point and pole) <b><br>
−Jq</b>[<i>lon0/</i>[<i>lat0/</i>]]<i>scale</i>
(Cylindrical Equidistant) <b><br>
−Jt</b><i>lon0/</i>[<i>lat0/</i>]<i>scale</i> (TM -
Transverse Mercator) <b><br>
−Ju</b><i>zone/scale</i> (UTM - Universal Transverse
Mercator) <b><br>
−Jy</b>[<i>lon0/</i>[<i>lat0/</i>]]<i>scale</i>
(Cylindrical Equal-Area)</p>
<p style="margin-left:22%; margin-top: 1em"><b>CONIC
PROJECTIONS:</b></p>
<p style="margin-left:22%; margin-top: 1em"><b>−Jb</b><i>lon0/lat0/lat1/lat2/scale</i>
(Albers) <b><br>
−Jd</b><i>lon0/lat0/lat1/lat2/scale</i> (Conic
Equidistant) <b><br>
−Jl</b><i>lon0/lat0/lat1/lat2/scale</i> (Lambert Conic
Conformal) <b><br>
−Jpoly</b>/[<i>lon0/</i>[<i>lat0/</i>]]<i>scale</i>
((American) Polyconic)</p>
<p style="margin-left:22%; margin-top: 1em"><b>AZIMUTHAL
PROJECTIONS:</b></p>
<p style="margin-left:22%; margin-top: 1em"><b>−Ja</b><i>lon0/lat0</i>[<i>/horizon</i>]<i>/scale</i>
(Lambert Azimuthal Equal-Area) <b><br>
−Je</b><i>lon0/lat0</i>[<i>/horizon</i>]<i>/scale</i>
(Azimuthal Equidistant) <b><br>
−Jf</b><i>lon0/lat0</i>[<i>/horizon</i>]<i>/scale</i>
(Gnomonic) <b><br>
−Jg</b><i>lon0/lat0</i>[<i>/horizon</i>]<i>/scale</i>
(Orthographic) <b><br>
−Jg</b><i>lon0/lat0/altitude/azimuth/tilt/twist/Width/Height/scale</i>
(General Perspective). <b><br>
−Js</b><i>lon0/lat0</i>[<i>/horizon</i>]<i>/scale</i>
(General Stereographic)</p>
<p style="margin-left:22%; margin-top: 1em"><b>MISCELLANEOUS
PROJECTIONS:</b></p>
<p style="margin-left:22%; margin-top: 1em"><b>−Jh</b>[<i>lon0/</i>]<i>scale</i>
(Hammer) <b><br>
−Ji</b>[<i>lon0/</i>]<i>scale</i> (Sinusoidal) <b><br>
−Jkf</b>[<i>lon0/</i>]<i>scale</i> (Eckert IV) <b><br>
−Jk</b>[<b>s</b>][<i>lon0/</i>]<i>scale</i> (Eckert
VI) <b><br>
−Jn</b>[<i>lon0/</i>]<i>scale</i> (Robinson) <b><br>
−Jr</b>[<i>lon0/</i>]<i>scale</i> (Winkel Tripel)
<b><br>
−Jv</b>[<i>lon0/</i>]<i>scale</i> (Van der Grinten)
<b><br>
−Jw</b>[<i>lon0/</i>]<i>scale</i> (Mollweide)</p>
<p style="margin-left:22%; margin-top: 1em"><b>NON-GEOGRAPHICAL
PROJECTIONS:</b></p>
<p style="margin-left:22%; margin-top: 1em"><b>−Jp</b>[<b>a</b>]<i>scale</i>[<i>/origin</i>][<b>r</b>|<b>z</b>]
(Polar coordinates (theta,r)) <b><br>
−Jx</b><i>x-scale</i>[<b>d</b>|<b>l</b>|<b>p</b><i>pow</i>|<b>t</b>|<b>T</b>][<i>/y-scale</i>[<b>d</b>|<b>l</b>|<b>p</b><i>pow</i>|<b>t</b>|<b>T</b>]]
(Linear, log, and power scaling)</p>
<a name="OPTIONS"></a>
<h2>OPTIONS</h2>
<p style="margin-left:11%; margin-top: 1em">No space
between the option flag and the associated arguments.</p>
<table width="100%" border=0 rules="none" frame="void"
cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−A</b></p> </td>
<td width="8%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Force 1:1 scaling,
i.e., output (or input, see <b>−I</b>) data are in
actual projected meters. To specify other units, append
<b>k</b> (km), <b>m</b> (mile),<b>n</b> (nautical mile),
<b>i</b> (inch), <b>c</b> (cm), or <b>p</b> (points).
Without <b>−A</b>, the output (or input, see
<b>−I</b>) are in the units specified by
<b><A HREF="gmtdefaults.html#MEASURE_UNIT">MEASURE_UNIT</A></b> (but see <b>−M</b>).</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−C</b></p> </td>
<td width="8%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Let projected
coordinates be relative to projection center [Default is
relative to lower left corner]. Optionally, add offsets in
the projected units to be added (or subtracted when
<b>−I</b> is set) to (from) the projected coordinates,
such as false eastings and northings for particular
projection zones [0/0].</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−D</b></p> </td>
<td width="8%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top"><i>x_inc</i> [and
optionally <i>y_inc</i>] is the grid spacing. Optionally,
append a suffix modifier. <b>Geographical (degrees)
coordinates</b>: Append <b>m</b> to indicate arc minutes or
<b>c</b> to indicate arc seconds. If one of the units
<b>e</b>, <b>k</b>, <b>i</b>, or <b>n</b> is appended
instead, the increment is assumed to be given in meter, km,
miles, or nautical miles, respectively, and will be
converted to the equivalent degrees longitude at the middle
latitude of the region (the conversion depends on
<b><A HREF="gmtdefaults.html#ELLIPSOID">ELLIPSOID</A></b>). If /<i>y_inc</i> is given but set to 0 it
will be reset equal to <i>x_inc</i>; otherwise it will be
converted to degrees latitude. <b>All coordinates</b>: If
<b>=</b> is appended then the corresponding max <i>x</i>
(<i>east</i>) or <i>y</i> (<i>north</i>) may be slightly
adjusted to fit exactly the given increment [by default the
increment may be adjusted slightly to fit the given domain].
Finally, instead of giving an increment you may specify the
<i>number of nodes</i> desired by appending <b>+</b> to the
supplied integer argument; the increment is then
recalculated from the number of nodes and the domain. The
resulting increment value depends on whether you have
selected a gridline-registered or pixel-registered grid; see
Appendix B for details. Note: if
<b>−R</b><i>grdfile</i> is used then grid spacing has
already been initialized; use <b>−D</b> to override
the values.</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−E</b></p> </td>
<td width="8%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Set the resolution
for the new grid in dots per inch.</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−F</b></p> </td>
<td width="8%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Toggle between
pixel and gridline node registration [Default is same as
input].</p> </td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−I</b></p> </td>
<td width="8%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Do the Inverse
transformation, from rectangular to geographical.</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−M</b></p> </td>
<td width="8%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Append <b>c</b>,
<b>i</b>, or <b>m</b> to indicate that cm, inch, or meter
should be the projected measure unit [Default is set by
<b><A HREF="gmtdefaults.html#MEASURE_UNIT">MEASURE_UNIT</A></b> in .gmtdefaults4]. Cannot be used with
<b>−A</b>.</p> </td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−N</b></p> </td>
<td width="8%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Set the number of
grid nodes in the new grid.</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−R</b></p> </td>
<td width="8%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top"><i>xmin</i>,
<i>xmax</i>, <i>ymin</i>, and <i>ymax</i> specify the Region
of interest. For geographic regions, these limits correspond
to <i>west, east, south,</i> and <i>north</i> and you may
specify them in decimal degrees or in
[+-]dd:mm[:ss.xxx][W|E|S|N] format. Append <b>r</b> if lower
left and upper right map coordinates are given instead of
w/e/s/n. The two shorthands <b>−Rg</b> and
<b>−Rd</b> stand for global domain (0/360 and
-180/+180 in longitude respectively, with -90/+90 in
latitude). Alternatively, specify the name of an existing
grid file and the <b>−R</b> settings (and grid
spacing, if applicable) are copied from the grid. For
calendar time coordinates you may either give (a) relative
time (relative to the selected <b><A HREF="gmtdefaults.html#TIME_EPOCH">TIME_EPOCH</A></b> and in the
selected <b><A HREF="gmtdefaults.html#TIME_UNIT">TIME_UNIT</A></b>; append <b>t</b> to
<b>−JX</b>|<b>x</b>), or (b) absolute time of the form
[<i>date</i>]<b>T</b>[<i>clock</i>] (append <b>T</b> to
<b>−JX</b>|<b>x</b>). At least one of <i>date</i> and
<i>clock</i> must be present; the <b>T</b> is always
required. The <i>date</i> string must be of the form
[-]yyyy[-mm[-dd]] (Gregorian calendar) or yyyy[-Www[-d]]
(ISO week calendar), while the <i>clock</i> string must be
of the form hh:mm:ss[.xxx]. The use of delimiters and their
type and positions must be exactly as indicated (however,
input, output and plot formats are customizable; see
<b><A HREF="gmtdefaults.html">gmtdefaults</A></b>). You may ask to project only a subset of
the grid by specifying a smaller input <i>w/e/s/n</i> region
[Default is the region given by the grid file].</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−S</b></p> </td>
<td width="8%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Select the
interpolation mode by adding <b>b</b> for B-spline
smoothing, <b>c</b> for bicubic interpolation, <b>l</b> for
bilinear interpolation, or <b>n</b> for nearest-neighbor
value (for example to plot categorical data). Optionally,
prepend <b>-</b> to switch off antialiasing. Add
<b>/</b><i>threshold</i> to control how close to nodes with
NaNs the interpolation will go. A <i>threshold</i> of 1.0
requires all (4 or 16) nodes involved in interpolation to be
non-NaN. 0.5 will interpolate about half way from a non-NaN
value; 0.1 will go about 90% of the way, etc. [Default is
bicubic interpolation with antialiasing and a threshold of
0.5].</p> </td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">
<p style="margin-top: 1em" valign="top"><b>−V</b></p> </td>
<td width="8%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Selects verbose
mode, which will send progress reports to stderr [Default
runs "silently"].</p></td>
</table>
<a name="GRID FILE FORMATS"></a>
<h2>GRID FILE FORMATS</h2>
<p style="margin-left:11%; margin-top: 1em">By default
<b><A HREF="GMT.html">GMT</A></b> writes out grid as single precision floats in a
COARDS-complaint netCDF file format. However, <b><A HREF="GMT.html">GMT</A></b> is
able to produce grid files in many other commonly used grid
file formats and also facilitates so called
"packing" of grids, writing out floating point
data as 2- or 4-byte integers. To specify the precision,
scale and offset, the user should add the suffix
<b>=</b><i>id</i>[<b>/</b><i>scale</i><b>/</b><i>offset</i>[<b>/</b><i>nan</i>]],
where <i>id</i> is a two-letter identifier of the grid type
and precision, and <i>scale</i> and <i>offset</i> are
optional scale factor and offset to be applied to all grid
values, and <i>nan</i> is the value used to indicate missing
data. When reading grids, the format is generally
automatically recognized. If not, the same suffix can be
added to input grid file names. See <b><A HREF="grdreformat.html">grdreformat</A></b>(1)
and Section 4.17 of the GMT Technical Reference and Cookbook
for more information.</p>
<p style="margin-left:11%; margin-top: 1em">When reading a
netCDF file that contains multiple grids, <b><A HREF="GMT.html">GMT</A></b> will
read, by default, the first 2-dimensional grid that can find
in that file. To coax <b><A HREF="GMT.html">GMT</A></b> into reading another
multi-dimensional variable in the grid file, append
<b>?</b><i>varname</i> to the file name, where
<i>varname</i> is the name of the variable. Note that you
may need to escape the special meaning of <b>?</b> in your
shell program by putting a backslash in front of it, or by
placing the filename and suffix between quotes or double
quotes. The <b>?</b><i>varname</i> suffix can also be used
for output grids to specify a variable name different from
the default: "z". See <b><A HREF="grdreformat.html">grdreformat</A></b>(1) and
Section 4.18 of the GMT Technical Reference and Cookbook for
more information, particularly on how to read splices of 3-,
4-, or 5-dimensional grids.</p>
<a name="EXAMPLES"></a>
<h2>EXAMPLES</h2>
<p style="margin-left:11%; margin-top: 1em">To transform
the geographical grid dbdb5.grd onto a pixel Mercator grid
at 300 dpi, run</p>
<p style="margin-left:11%; margin-top: 1em"><b>grdproject</b>
dbdb5.grd <b>−R</b>20/50/12/25
<b>−Jm</b>0.25<b>i −E</b>300 <b>−F
−G</b>dbdb5_merc.grd</p>
<p style="margin-left:11%; margin-top: 1em">To inversely
transform the file topo_tm.grd back onto a geographical
grid, use</p>
<p style="margin-left:11%; margin-top: 1em"><b>grdproject</b>
topo_tm.grd <b>−R</b>-80/-70/20/40
<b>−Jt</b>-75/1:500000 <b>−I −D</b>5<b>m
−V −G</b>topo.grd</p>
<p style="margin-left:11%; margin-top: 1em">This assumes,
of course, that the coordinates in topo_tm.grd were created
with the same projection parameters. <br>
To inversely transform the file topo_utm.grd (which is in
UTM meters) back to a geographical grid we specify a
one-to-one mapping with meter as the measure unit:</p>
<p style="margin-left:11%; margin-top: 1em"><b>grdproject</b>
topo_utm.grd <b>−R</b>203/205/60/65
<b>−Ju</b>5/1:1 <b>−I −Mm
−G</b>topo.grd <b>−V</b></p>
<a name="RESTRICTIONS"></a>
<h2>RESTRICTIONS</h2>
<p style="margin-left:11%; margin-top: 1em">The boundaries
of a projected (rectangular) data set will not necessarily
give rectangular geographical boundaries (Mercator is one
exception). In those cases some nodes may be unconstrained
(set to NaN). To get a full grid back, your input grid may
have to cover a larger area than you are interested in.</p>
<a name="SEE ALSO"></a>
<h2>SEE ALSO</h2>
<p style="margin-left:11%; margin-top: 1em"><i><A HREF="GMT.html">GMT</A></i>(1),
<i><A HREF="gmtdefaults.html">gmtdefaults</A></i>(1), <i><A HREF="mapproject.html">mapproject</A></i>(1)</p>
<hr>
</body>
</html>
distrib
>
Fedora
>
18
>
x86_64
>
media
>
updates
>
by-pkgid
>
fa8759c1f2240ce030f5ac6d5041a2a1
>
files
>
400
